A howitzer is a crude-looking weapon, essentially a small smokestack with a door at the bottom that allows the insertion of breadbox-sized shells. but operating one requires a year of specialized schooling. That’s because howitzers, like most artillery guns, are “indirect fire” weapons-that is, if you aim directly at your target, you’ll literally miss by a mile, and probably by several. Adjustments have to be made for distance, wind, temperature, atmospheric density, humidity, the amount of wear in the barrel and the spin of the earth (aim left in the Northern Hemisphere, right under southern skies). Even then, most of the shell’s explosive force will not end up precisely where intended. Then, 30 seconds of frenzy among a crew of six sees a new shell dragged into the gun, and you can try again. For all this bother, though, howitzers remain the weapon of choice for delivering destruction at a distance.

A military expert, given a clean sheet of paper and asked to sketch out the howitzer’s ideal replacement, might end up with something like this: fires weightless and unlimited ammunition, is mountable on aircraft or ground vehicles, can be aimed directly at a target, reloads instantly, tracks fast-moving targets, shoots with pinpoint precision, creates no risk of collateral damage. In the end, he or she would have essentially described a class of weapon that could play a significant role in the next major U.S. armed conflict-weapons that hurl photons instead of chunks of metal.

The U.S. military is gearing up for laser warfare.

Of course, the idea of using high-powered lasers to destroy enemy missiles has been widely publicized ever since President Ronald Reagan pushed the “Star Wars” program-the Strategic Defense Initiative-in the early 1980s. But far less recognized-and less speculative-is the prospect that more down-to-earth laser weapons may soon revolutionize all types of combat, thanks to an intense, four-decade-long research and development effort that’s poised to pay battlefield dividends. From versions that fill a 747 airplane to devices that fit in a Humvee, lasers are already destroying military targets in tests and are likely to be deployed over the next decade in everything from full-scale warfare to peacekeeping actions to terrorist encounters.

The U.S. military and its contractors have been exceedingly discreet about these programs. And for good reason. Laser weapons remain highly controversial. In the early 1990s, for example, protests from groups that deem battlefield lasers inhumane because of their potential for blinding both civilians and combatants forced the military to shelve a secret laser system that would literally have given eyeball-blasting capabilities to foot soldiers. Though the newer programs appear to skirt international prohibitions on blinding weapons, protests are likely to be revived as the weapons come online. Stephen Goose, program director of the arms division of Human Rights Watch, concedes that the quiet fashion in which battlefield laser systems are being developed has temporarily taken them off of human- rights groups’ radar screens. But that may be about to change. “No one is reviewing how these systems are being implemented,” he says. “But questions need to be raised.”

Despite such concerns, however, the military is going full speed ahead-and some experts feel laser weapons will soon give American troops a battlefield edge. “The introduction of optical and other directed-energy weapons, including advanced nonlethal weapons, will be as significant as the introduction of firearms and artillery was to the modern world,” says Robert Bunker, an adjunct professor in the National Security Studies program at California State University, San Bernardino, and a professor at American Military University. Indeed, China and Russia also have reportedly been developing laser weapons for at least a decade, though in less powerful and accurate form.